How to Enable Diag Port on Google Pixel Models up to 5a 5G

Are you looking to unlock the Diag (Diagnostic) port on your Google Pixel device? Whether you’re a developer, a tech enthusiast, or simply someone wanting to access advanced debugging features, enabling the Diag port can open up numerous opportunities for device diagnostics, debugging, and deeper system analysis. In this comprehensive guide, we will walk you through the process of enabling the Diag port on Google Pixel models including Pixel 3, Pixel 4, and Pixel 5 series running on Qualcomm chipsets.

What is a Diag Port?

The Diag port, short for Diagnostic port, is used by mobile devices to communicate with a computer for diagnostic purposes. This port provides access to diagnostic interfaces like QPST (Qualcomm Product Support Tools), which is crucial for low-level communication with the phone’s modem, allowing tasks such as:

  • Debugging cellular issues
  • Modifying the radio settings
  • Conducting advanced diagnostics on network connections
  • To backu QCN file.
  • To Repair IMEI

On Google Pixel devices, accessing this port requires some extra steps as it’s not enabled by default.

Prerequisites

Before you begin, make sure you have the following tools ready:

  • A Google Pixel device (up to Pixel 5a 5G and lower).
  • A Windows PC or Linux machine with ADB (Android Debug Bridge) installed. You can install ADB by following this guide.
  • USB drivers for your Pixel device.
  • Root access to your Google Pixel device. While some methods may not require root, most advanced diagnostics do. Tutorial to root your Google Pixel.
  • A USB data cable for connecting your phone to your computer.
  • QPST or similar diagnostic tools installed on your computer.
  • Qualcomm Drivers

Step-by-Step Guide to Enabling Diag Port on Google Pixel Devices

1. Enable Developer Options and USB Debugging

First, you need to enable Developer Options on your Pixel device:

  1. Go to Settings > About Phone.
  2. Scroll down and tap on Build Number seven times until you see a notification that Developer Mode has been enabled.
  3. Go back to the Settings menu, and you should see Developer Options appear.
  4. Inside Developer Options, enable USB Debugging.

USB Debugging option Android settings

2. Connect Your Pixel to the Computer

Now, connect your Google Pixel device to your computer using a USB cable. Once connected, authorize your PC to communicate with the phone if prompted.

3. Verify ADB Connection

On your PC, open a command prompt or terminal and enter the following command:

adb devices

If your device appears in the list, the connection is successful. If not, check your USB drivers and make sure USB Debugging is enabled on your Pixel.

4. Enter Diagnostic Mode

To enable the Diag port, you’ll need to send a special command to the Pixel’s Qualcomm modem. In some cases, root access is required for this step.

If your device is rooted:

adb shell
su

resetprop ro.bootmode usbradio
resetprop ro.build.type userdebug
setprop sys.usb.config diag,diag_mdm,adb

diag_mdlog

This command forces your device to enter Diagnostic Mode, where both ADB and the Diag port are enabled. On your device, drag down the notifications and select  USB options and change it to ‘File transfer/ Android Auto’ from ‘No data transfer’ and vice verse as you can in the photo below.

 

5. Confirm Diag Mode is Enabled

Close the existing command window. To confirm whether the Diag port is active, you can use the following command:

adb shell getprop sys.usb.config

If “diag” appears in the output along with “adb,” you have successfully enabled the Diag port.

You can also open the device manager on your PC. Under the ports (COM & LPT) you should see a Qualcomm HS-USB Diagnostic 903A depending on your phone.

6. Use QPST or QXDM for Diagnostics

Now that the Diag port is enabled, you can open QPST or QXDM (Qualcomm Diagnostic Monitor) to perform the necessary diagnostics on your device. These tools will allow you to interact with the modem for deeper analysis, including testing network performance, configuring radio settings, and gathering diagnostic logs.

Troubleshooting Common Issues

Here are some common issues you may face while enabling the Diag port on your Google Pixel:

  • Device not detected by ADB: Ensure USB Debugging is enabled, and you have the correct drivers installed.
  • Permission Denied Errors: If you’re getting permission denied errors, make sure your device is rooted. Some commands require root access.
  • Diag Port Not Appearing: If the Diag port isn’t showing up in QPST or QXDM, try restarting both your phone and computer and repeat the process.

Safety Notes and Risks

Enabling the Diag port and performing diagnostic operations can give you deep access to your Pixel’s modem and radio. This comes with certain risks, including:

  • Voiding Your Warranty: Some manufacturers may void your warranty if you enable diagnostic features.
  • Potential for Bricking: Incorrectly changing modem settings can potentially render your phone inoperable.
  • Security Concerns: If left enabled, the Diag port could expose your device to security vulnerabilities. Be sure to disable it when not in use.

Conclusion

Enabling the Diag port on your Google Pixel (up to the 5a 5G) opens the door to advanced debugging and diagnostic features, useful for both developers and tech enthusiasts. While the process involves some complexity—particularly if your device needs to be rooted—following these steps carefully will guide you to success.

For any additional help, make sure to refer to forums like XDA Developers, which offer insights from other users performing similar tasks.

FAQs

Q: Does enabling the Diag port require root access on all Google Pixel models?
A: While it’s possible to enable Diag mode without root on some devices, most advanced diagnostic commands will require root access, particularly on Google Pixel models.

Q: Can I undo the changes after enabling the Diag port?
A: Yes, you can disable the Diag port by resetting the USB configuration to default. Run the following command:

adb shell setprop sys.usb.config mtp,adb

Q: Is there any other alternative for non-rooted devices?
A: Some third-party applications may allow access to certain diagnostic features without root, but full access to the Diag port typically requires root privileges.

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Imran Aftab
 

Hello, I'm Imran Aftab, a tech enthusiast using Android, iOS, and Windows. Hardware expert for Gaming & Crypto mining rigs. I have been writing on tech since 2013, starting with ohguideme, then Androidcentral. I have written and published several guides and tutorials on how to root Android, flash custom ROM, recovery, and jailbreak iPhone, and have written several guides on how to bypass FRP. I also worked in a phone repair shop, so I have pretty good experience with mobile software and troubleshooting. So, all the guides you see here have been tested and confirmed to work.

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